Process for making non-particulate detergent product readily dispersible in water

ABSTRACT

A process for producing a water-dispersible non-particulate detergent product includes the step of providing a particulate detergent composition. The process further includes the step of adding a flow aid to the particulate detergent composition in a range of from about 0.1% to about 25% by weight of the particulate detergent composition. The process then includes the step of compacting the particulate detergent composition having the flow aid by applying a pressure in an amount sufficient to form the water-dispersible non-particulate detergent product having a density of at least about 1000 g/l. This process enables the manufacture of a rapidly dispersing non-particulate detergent composition that sinks in water.

This application is a 371 of PCT/IB99/00710 filed Apr. 21, 1999 whichclaims the benefit of U.S. Provisional Application No. 60/083,264 filedApr. 27, 1998.

TECHNICAL FIELD

The present invention relates to detergent compositions innon-particulate form. More particularly, the invention relates to aprocess for improving the dispersibility of a non-particulate detergentcomposition, e.g., tablet, block or bar, in water, by enabling themanufacture of a non-particulate detergent product that sinks in waterand rapidly disintegrates and dissolves in water

BACKGROUND OF THE INVENTION

Non-particulate detergents are an alternative to granular or particulateforms of detergents for simplifying the dosing of such detergents forautomatic washing machines, such as laundry or dishwashing machines.Such non-particulate detergents are usually supplied in the form ofbars, tablets or briquettes. Such non-particulate detergents not onlyprevent spillage of the detergent composition but also eliminate theneed for the consumer to estimate the correct dosage of the detergentcomposition per wash. Further, such non-particulate detergents alsominimize the contact by the consumer with the detergent.

An important factor for successful performance of a non-particulatedetergent is its ability to dissolve in the washing machine in acontrolled manner according to a desired dissolution profile during theprogram cycle of the machine. Another important performance factor isthat the non-particulate detergent should be hard enough to facilitateeasy handling of the detergent prior to use, so that it does notinadvertently lose its structure, crumble, or deteriorate, both duringthe packaging, transport and storage and during handling by the endconsumer prior to actual use. Such performance aspects are an importantfeature of the non-particulate detergent, and although they are notnecessarily the focus of the present invention, they are inherently apart of the background of the present invention.

Additionally, a very desirable feature of a non-particulate detergent,such as for example, a tablet, is its ability to sink in water andrapidly disperse in water to form a wash solution. In order to sink inwater, a detergent tablet must have a density greater than 1000 g/l andin order to disperse in water, a detergent tablet must be able to breakup in water. However, when laundry tablets are made from low bulkdensity detergents, such as those made by spray dried processes, whereinthe detergent powder has a bulk density less than about 650 g/l, theproblem frequently encountered is that the force required to compact thedetergent powder into tablets having a density of at least 1000 g/l isso high that the detergent tablets do not readily disperse in water.This problem is further escalated by the fact that detergent powdersmade from spray dried processes tend to be more porous and sticky. Thuswhen these detergent powders are pressed into tablets having a densityof at least 1000 g/l, the powder particles stick together andconsequently the tablet does not readily break up and dissolve in water.Conversely, if the tablets made from low bulk density detergent powdersare compacted using a lower force, they generally disperse in water butat a slower rate because they have a density less than 1000 g/l and thustend to float in water before fully dispersing in water.

The above problem is usually not encountered when making detergenttablets from a detergent powder made by agglomeration processes becausedetergent powders made by agglomeration processes usually have a bulkdensity in a range of about 700 g/l to about 850 g/l and consequently,the force required to compress the powder into a tablet having a densityof at least 1000 g/l is not so high. Thus detergent tablets made bycompacting detergent powders made from agglomeration process usuallysink in water. However, agglomeration process detergents or“agglomerates”, which inherently have higher density than spray driedprocess detergents or “spray dried granules”, generally exhibit slowerdissolution rates in water, as compared to spray dried granules.

Thus the production of detergent tablets is a complex matter. Itinvolves more than the mere selection of components or the compressionof a particular detergent composition into a tablet. The tablet must becapable of withstanding the shocks of packaging, handling anddistribution without crumbling. In other words the tablet must bestrong. But the tablet must also have a satisfactory rate ofdisintegration when immersed in water. The tablets known so far havegenerally shown too long a disintegration time, in favor of theirstrength, or they have had a very low strength, in favor of theirshorter disintegration time.

It is highly desirable to have a laundry detergent tablet with a corewhich is formed by compressing a particulate material which has adetersive surfactant and a builder and wherein the particulate materialis processed in a manner so as to make the individual particles stickyenough to stay together when the material is compressed into a tabletform, yet not too sticky to not disintegrate rapidly when immersed inwater. This becomes a very challenging problem in light of theadditional desirable requirement that the detergent tablet, aftercompaction, have a density of at least 1000 g/l so that it sinks inwater.

This kind of a tablet performance has heretofore not been available andthis level of performance requires not only careful selection of thetype of detergent that makes up the core, but also requires novel waysto surface treat the detergent particles prior to compaction so as havejust the right amount of stickiness. The present invention overcomes theproblems as outlined above.

BACKGROUND ART

The prior art is replete with methods of forming tablets and coatingtablets.

One approach has been to use acetate salt to improve the dissolutionrate of detergents compressed in the form of tablets. EP-A-0002293,published on Jun. 13, 1979, discloses detergent tablets containinghydrated salt. The preferred hydrate salt is a mixture of sodium acetatetrihydrate and sodium metaborate tetrahydrate.

Another approach known in the art is to use effervescent aids to improvetablet disintegration. CA-A-2040307 discloses lundry detergent tabletscomprising anionic surfactants mixed with sodium carbonate and citricacid.

As far as coated tablets are concerned, GB-A-0 989 683, published onApr. 22, 1965, discloses a process for preparing a particulate detergentfrom surfactants and inorganic salts; spraying on water-solublesilicate; and pressing the detergent particles into a solidform-retaining tablet. Finally a readily water-soluble organicfilm-forming polymer (for example, polyvinyl alcohol) provides a coatingto make the detergent tablet resistant to abrasion and accidentalbreakage.

European publication, EP-A-0 002 293, published on Jun. 13, 1979,discloses a tablet coating comprising hydrated salt such as acetate,metaborate, orthophosphate, tartrate, and sulphate. Another Euaopeanpublication, EP-A-0 716 144, published on Jun. 12, 1996, also discloseslaundry detergent tablets with water-soluble coatings which may beorganic polymers including acrylic/maleic co-polymer, polyethyleneglycol, PVPVA, and sugar.

SUMMARY OF THE INVENTION

The invention meets the needs above by providing a process for producinga water-dispersible non-particulate detergent product. Specifically, inone aspect of the present invention, the process comprises the step ofproviding a particulate detergent composition. The process furtherincludes the step of adding a flow aid to the particulate detergentcomposition in a range of from about 0.1% to about 25% by weight of theparticulate detergent composition. The process then includes the step ofcompacting the particulate detergent composition having the flow aid byapplying a pressure in an amount sufficient to form thewater-dispersible non-particulate detergent product having a density ofat least about 1000 g/l.

In another aspect of the present invention, a method of launderingfabric materials in a washing machine is provided. The method includesthe steps of providing a flexible porous bag adapted for receiving anon-particulate detergent product, providing a non-particulate detergentproduct, placing the non-particulate detergent product within theflexible porous bag, and placing the flexible porous bag containing thedetergent product in the washing machine with the fabric materials to bewashed. The flexible porous bag is adapted for permitting entry of anaqueous washing medium through the bag, thereby dissolving thenon-particulate detergent product placed therein, into the aqueouswashing medium, and releasing a resultant wash solution from inside ofthe bag to outside of the bag and into the aqueous wash medium during awash cycle.

In yet another aspect of the present invention, a method of launderingsoiled clothes includes the step of immersing the soiled clothes in anaqueous medium containing an effective amount of a non-particulatedetergent product made by a process which includes the steps ofproviding a particulate detergent composition, adding a flow aid to theparticulate detergent composition in a range of from about 0.1% to about25% by weight of the particulate detergent composition and compactingthe particulate detergent composition having the flow aid by applying apressure in an amount sufficient to form the water-dispersiblenon-particulate detergent product having a density of at least about1000 g/l.

In yet another aspect of the present invention, a water-dispersiblenon-particulate detergent product is disclosed. The product includes acore formed by compacting a particulate detergent composition to adensity of at least about 1000 g/l. The particulate detergentcomposition has a bulk density in a range of from about 600 g/l to about850 g/l. The particulate detergent composition comprises a flow aid in arange of from about 0.1% to about 25% by weight of the particulatedetergent composition.

DETAILED DESCRIPTION OF THE INVENTION Process

In the preferred embodiment of the present invention, the processincludes the step of providing a particulate detergent composition.

The Particulate Detergent Composition

The term “particulate” as used herein means forms such as powders,granules, particles, flakes and other similar particulate forms that arecapable of being compacted into a more dense non-particulate form.

In particular for laundry tablets, detergent particles havingingredients such as builder and surfactant can be spray-dried in aconventional manner and then compacted at a suitable pressure. Thesurfactants and builders normally provide a substantial part of thecleaning power of the tablet. The term “builder” is intended to mean allmaterials which tend to remove calcium ion from solution, either by ionexchange, complexation, sequestration or precipitation.

The particulate material used for making the detergent tablet providedin this invention can be made by any particulation or granulationprocess. An example of such a process is spray drying (in a co-currentor counter current spray drying tower) which typically gives“spray-dried” detergent granules having low bulk densities of 600g/l orlower. Particulate materials of higher density can be prepared bygranulation and densification in a high shear batch mixer/granulator orby a continuous granulation and densification process (e.g. usingLodige® CB and/or Lodige® KM mixers). Other suitable processes includefluid bed processes, compaction processes (e.g. roll compaction),extrusion, as well as any particulate material made by any chemicalprocess like flocculation, crystallization sentering, etc. Theindividual particles can also be in any other form, such as for example,particle, granule, sphere or grain.

The particulate materials may be mixed together by any conventionalmeans, for example, a concrete mixer, Nauta mixer, ribbon mixer or anyother. Alternatively the mixing process may be carried out continuouslyby metering each component by weight on to a moving belt, and blendingthem in one or more drum(s) or mixer(s). A liquid spray-on to the mix ofparticulate materials (e.g. non-ionic surfactants) may be carried out.Other liquid ingredients may also be sprayed on to the mix ofparticulate materials either separately or premixed. For example perfumeand slurries of optical brighteners may be sprayed. A finely dividedflow aid (dusting agent such as zeolites, carbonates, silicas) can beadded to the particulate materials after spraying the non-ionic,preferably towards the end of the process, to make the mix less sticky.

The detergent particles can be made by an agglomerate process comprisingthe steps of:

i) admixing one or more detergent surfactants, a perborate component andan acid source and optionally other detergent ingredients to form amixture; and

ii) agglomerating the mixture to form agglomerated particles or“agglomerates”.

Typically, such an agglomeration process involves mixing an effectiveamount of powder, including the acid source, with a high activesurfactant paste in one or more agglomerators such as a panagglomerator, a Z-blade mixer or more preferably in-line mixers,preferably two, such as those manufactured by Schugi (Holland) BV, 29Chroomstraat 8211 AS, Lelystad, Netherlands, and Gebruder LodigeMaschinenbau GmbH, D4790 Paderbom 1, Elsenerstrasse 7-9, Postfach 2050,Germany. Preferably a high shear mixer is used, such as a Lodige CB(Trade Name). Most preferably, a high shear mixer is used in combinationwith a low shear mixer, such as a Lodige CB (Trade Name) and a Lodige KM(Trade name) or Schugi KM (Trade Name). Optionally, only one or more lowshear mixer are used. Preferably, the agglomerates are thereafter driedand/ or cooled.

Another agglomeration process involves mixing of various components ofthe final agglomorate in different stages, using a fluidized bed. Forexample, a preferred particulate detergent in accordance with thepresent invention can be agglomerated by addition, preferably byspraying on, of nonionic, anionic surfactants and optionally a wax, ormixtures thereof, to the acid source in powdered form and other optionalingredients. Then, additional components, including the perborate bleachand optinally the alkali source or part thereof, can be added andagglomerated in one or more stages, thus forming the final agglomerateparticle.

The agglomerates may take the form of flakes, prills, marumes, noodles,ribbons, but preferably take the form of granules. A preferred way toprocess the particles is by agglomerating powders (e.g. aluminosilicate,carbonate) with high active surfactant pastes and to control theparticle size of the resulting agglomerates within specified limits.Typical particle sizes are from 0.10 mm to 5.0 mm in diameter,preferably from 0.25 mm to 3.0 mm in diameter, most preferably from 0.40mm to 1.00 mm in diameter. Typically, the “agglomerates” have a bulkdensity desirably of at least 700 g/l and preferably, in a range of fromabout 700 g/l to about 900 g/l.

A high active surfactant paste comprising a mix of, typically, from 50%by weight to 95% by weight, preferably 70% by weight to 85% by weight ofsurfactant, and optionally it can contain an appropriate acid source.The paste may be pumped into the agglomerator at a temperature highenough to maintain a pumpable viscosity, but low enough to avoiddegradation of the anionic surfactants used. An operating temperature ofthe paste of 50° C. to 80° C. is typical. Such pastes and methods formaking and processing such pastes is for example described in WO93/03128. In an especially preferred embodiment of the presentinvention, the detergent particles made by agglomeration process have abulk density of greater than about 600 g/l and the detergent is in theform of powder or a granulate.

In the preferred embodiment of the present invention, the particulatedetergent composition is a mixture of spray dried process andagglomeration process detergents, such that the final bulk density ofthe detergent composition is in a range of desirably, no greater thanabout 900 g/l, more desirably, in a range of from about 600 g/l to about850 g/l, and preferably, in a range of from about 625 g/l to about 725g/l. These ranges of bulk density are desirable because if the bulkdensity of the particulate detergent from which the tablet is to becompressed is greater than about 900 g/l, then the solubility of thedetergent tablet will be detrimentally affected. A bulk density lessthan about 600 g/l is undesirable because at values less than about 600g/l, the amount of pressure required to form a detergent tablet having adensity of at least 1000 g/l is so high that the tablet will not breakup easily in water and will not dissolve rapidly.

To achieve the desired bulk densities as set forth above, theparticulate detergent composition contains selected amounts of spraydried granules and detergent agglomerates in an optimum proportion. Inthis regard, the composition comprises desirably from about 40% to about80%, preferably from about 40% to about 60%, and more preferably fromabout 45% to about 55%, by weight, of spray dried. Desirably, thecomposition includes from about 20% to about 60%, preferably from about40% to about 60%, and more preferably from about 45% to about 55%, byweight, of agglomerates.

Dry Detergent Material

The starting dry detergent material of the present process preferablycomprises materials selected from the group consisting of carbonates,sulfates, carbonate/sulfate complexes, tripolyphosphates, tetrasodiumpyrophosphate, citrates, aluminosilicates, cellulose-based materials andorganic synthetic polymeric absorbent gelling materials. Morepreferably, the dry detergent material is selected from the groupconsisting of aluminosilicates, carbonates, sulfates, carbonate/sulfatecomplexes, and mixtures thereof. Most preferably, the dry detergentmaterial comprise a detergent aluminosilicate builder which arereferenced as aluminosilicate ion exchange materials and sodiumcarbonate.

The aluminosilicate ion exchange materials used herein as a detergentbuilder preferably have both a high calcium ion exchange capacity and ahigh exchange rate. Without intending to be limited by theory, it isbelieved that such high calcium ion exchange rate and capacity are afunction of several interrelated factors which derive from the method bywhich the aluminosilicate ion exchange material is produced. In thatregard, the aluminosilicate ion exchange materials used herein arepreferably produced in accordance with Corkill et al, U.S. Pat. No.4,605,509 (Procter & Gamble), the disclosure of which is incorporatedherein by reference.

Preferably, the alurninosilicate ion exchange material is in “sodium”form since the potassium and hydrogen forms of the instantaluminosilicate do not exhibit the as high of an exchange rate andcapacity as provided by the sodium form. Additionally, thealuminosilicate ion exchange material preferably is in over dried formso as to facilitate production of crisp detergent agglomerates asdescribed herein. The aluminosilicate ion exchange materials used hereinpreferably have particle size diameters which optimize theireffectiveness as detergent builders. The term “particle size diameter”as used herein represents the average particle size diameter of a givenaluminosilicate ion exchange material as determined by conventionalanalytical techniques, such as microscopic determination and scanningelectron microscope (SEM). The preferred particle size diameter of thealuminosilicate is from about 0.1 micron to about 10 microns, morepreferably from about 0.5 microns to about 9 microns. Most preferably,the particle size diameter is from about 1 microns to about 8 microns.

Preferably, the aluminosilicate ion exchange material has the formula

Na_(z)[(AlO₂)_(z).(SiO₂)_(y) ]xH₂O

wherein z and y are integers of at least 6, the molar ratio of z to y isfrom about 1 to about 5 and x is from about 10 to about 264. Morepreferably, the aluminosilicate has the formula

Na₁₂[(AlO₂)₁₂.(SiO₂)₁₂ ]xH₂O

wherein x is from about 20 to about 30, preferably about 27. Thesepreferred aluminosilicates are available commercially, for example underdesignations Zeolite A, Zeolite B and Zeolite X. Alternatively,naturally-occurring or synthetically derived aluminosilicate ionexchange materials suitable for use herein can be made as described inKrummel et al, U.S. Pat. No. 3,985,669, the disclosure of which isincorporated herein by reference.

The aluminosilicates used herein are further characterized by their ionexchange capacity which is at least about 200 mg equivalent of CaCO₃hardness/gram, calculated on an anhydrous basis, and which is preferablyin a range from about 300 to 352 mg equivalent of CaCO₃ hardness/gram.Additionally, the instant aluminosilicate ion exchange materials arestill further characterized by their calcium ion exchange rate which isat least about 2 grains Ca⁺⁺/gallon/minute/-gram/gallon, and morepreferably in a range from about 2 grainsCa⁺⁺/gallon/minute/-gram/gallon to about 6 grainsCa⁺⁺/gallon/minute/-gram/gallon.

Additionally, those builder materials discussed previously as anoptional coating agent can be used herein. These particular buildermaterials have the formula (M_(x))_(i) Ca_(y) (CO3)_(z) wherein x and iare integers from 1 to 15, y is an integer from 1 to 10, z is an integerfrom 2 to 25, M_(i) are cations, at least one of which is awater-soluble, and the equation Σ_(i=1-15)(x_(i) multiplied by thevalence of M_(i)) +2y=2z is satisfied such that the formula has aneutral or “balanced” charge. Additional details and examples of thesebuilder materials have been set forth previously and are incorporatedherein by reference. Preferably, these builder materials are selectedfrom the group consisting of Na₂Ca(CO₃)₂, K₂Ca(CO₃)₂, Na₂Ca₂(CO₃)_(3,)NaKCa(CO₃)₂, NaKCa₂(CO₃)₃, K₂Ca₂(CO₃)₃, and combinations thereof.

Adjunct Detergent Ingredients

The starting dry detergent material in the present process can includeadditional detergent ingredients and/or, any number of additionalingredients can be incorporated in the detergent composition duringsubsequent steps of the present process. These adjunct ingredientsinclude other detergency builders, bleaches, bleach activators, sudsboosters or suds suppressers, anti-tarnish and anticorrosion agents,soil suspending agents, soil release agents, germicides, pH adjustingagents, non-builder alkalinity sources, chelating agents, smectiteclays, enzymes, enzyme-stabilizing agents and perfumes. See U.S. Pat.No. 3,936,537, issued Feb. 3, 1976 to Baskerville, Jr. et al.,incorporated herein by reference.

Other builders can be generally selected from the various water-soluble,alkali metal, ammonium or substituted ammonium phosphates,polyphosphates, phosphonates, polyphosphonates, carbonates, borates,polyhydroxy sulfonates, polyacetates, carboxylates, andpolycarboxylates. Preferred are the alkali metal, especially sodium,salts of the above. Preferred for use herein are the phosphates,carbonates, C₁₀₋₁₈ fatty acids, polycarboxylates, and mixtures thereof.More preferred are sodium tripolyphosphate, tetrasodium pyrophosphate,citrate, tartrate mono- and di-succinates, and mixtures thereof (seebelow).

In comparison with amorphous sodium silicates, crystalline layeredsodium silicates exhibit a clearly increased calcium and magnesium ionexchange capacity. In addition, the layered sodium silicates prefermagnesium ions over calcium ions, a feature necessary to insure thatsubstantially all of the “hardness” is removed from the wash water.These crystalline layered sodium silicates, however, are generally moreexpensive than amorphous silicates as well as other builders.Accordingly, in order to provide an economically feasible laundrydetergent, the proportion of crystalline layered sodium silicates usedmust be determined judiciously.

The crystalline layered sodium silicates suitable for use hereinpreferably have the formula

 NaMSi_(x)O_(2x+1) .yH₂O

wherein M is sodium or hydrogen, x is from about 1.9 to about 4 and y isfrom about 0 to about 20. More preferably, the crystalline layeredsodium silicate has the formula

NaMSi₂O₅ .yH₂O

wherein M is sodium or hydrogen, and y is from about 0 to about 20.These and other crystalline layered sodium silicates are discussed inCorkill et al, U.S. Pat. No. 4,605,509, previously incorporated hereinby reference.

Specific examples of inorganic phosphate builders are sodium andpotassium tripolyphosphate, pyrophosphate, polymeric metaphosphatehaving a degree of polymerization of from about 6 to 21, andorthophosphates. Examples of polyphosphonate builders are the sodium andpotassium salts of ethylene diphosphonic acid, the sodium and potassiumsalts of ethane 1 -hydroxy- 1, 1 -diphosphonic acid and the sodium andpotassium salts of ethane, 1,1,2-triphosphonic acid. Other phosphorusbuilder compounds are disclosed in U.S. Pat. Nos. 3,159,581; 3,213,030;3,422,021; 3,422,137; 3,400,176 and 3,400,148, all of which areincorporated herein by reference.

Examples of nonphosphorus, inorganic builders are tetraboratedecahydrate and silicates having a weight ratio of SiO₂ to alkali metaloxide of from about 0.5 to about 4.0, preferably from about 1.0 to about2.4. Water-soluble, nonphosphorus organic builders useful herein includethe various alkali metal, ammonium and substituted ammoniumpolyacetates, carboxylates, polycarboxylates and polyhydroxy sulfonates.Examples of polyacetate and polycarboxylate builders are the sodium,potassium, lithium, ammonium and substituted ammonium salts of ethylenediamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid,mellitic acid, benzene polycarboxylic acids, and citric acid.

Polymeric polycarboxylate builders are set forth in U.S. Pat. No.3,308,067, Diehl, issued Mar. 7, 1967, the disclosure of which isincorporated herein by reference. Such materials include thewater-soluble salts of homo- and copolymers of aliphatic carboxylicacids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid,aconitic acid, citraconic acid and methylene malonic acid. Some of thesematerials are useful as the water-soluble anionic polymer as hereinafterdescribed, but only if in intimate admixture with the non-soap anionicsurfactant.

Other suitable polycarboxylates for use herein are the polyacetalcarboxylates described in U.S. Pat. No. 4,144,226, issued Mar. 13, 1979to Crutchfield et al, and U.S. Pat. No. 4,246,495, issued Mar. 27, 1979to Crutchfield et al, both of which are incorporated herein byreference. These polyacetal carboxylates can be prepared by bringingtogether under polymerization conditions an ester of glyoxylic acid anda polymerization initiator. The resulting polyacetal carboxylate esteris then attached to chemically stable end groups to stabilize thepolyacetal carboxylate against rapid depolymerization in alkalinesolution, converted to the corresponding salt, and added to a detergentcomposition. Particularly preferred polycarboxylate builders are theether carboxylate builder compositions comprising a combination oftartrate monosuccinate and tartrate disuccinate described in U.S. Pat.No. 4,663,071, Bush et al., issued May 5, 1987, the disclosure of whichis incorporated herein by reference.

Bleaching agents and activators are described in U.S. Pat. No.4,412,934, Chung et al., issued Nov. 1, 1983, and in U.S. Pat. No.4,483,781, Hartman, issued Nov. 20, 1984, both of which are incorporatedherein by reference. Chelating agents are also described in U.S. Pat.No. 4,663,071, Bush et al., from Column 17, line 54 through Column 18,line 68, incorporated herein by reference. Suds modifiers are alsooptional ingredients and are described in U.S. Pat. No. 3,933,672,issued Jan. 20, 1976 to Bartoletta et al., and U.S. Pat. No. 4,136,045,issued Jan. 23, 1979 to Gault et al., both incorporated herein byreference.

Suitable smectite clays for use herein are described in U.S. Pat. No.4,762,645, Tucker et al, issued Aug. 9, 1988, Column 6, line 3 throughColumn 7, line 24, incorporated herein by reference. Suitable additionaldetergency builders for use herein are enumerated in the Baskervillepatent, Column 13, line 54 through Column 16, line 16, and in U.S. Pat.No. 4,663,071, Bush et al, issued May 5, 1987, both incorporated hereinby reference.

The Non-particulate Detergent Product

The detergent tablets can be prepared simply by mixing the solidingredients together and compressing the mixture in a conventionaltablet press as used, for example, in the pharmaceutical industry.

The detergent tablets provided can be made in any size or shape and aredesirably surface treated with a flow aid according to the presentinvention. The detergent tablets provided may be manufactured by usingany compacting process, such as tabletting, briquetting, or extrusion,preferably tabletting. Suitable equipment includes a standard singlestroke or a rotary press (such as Courtoy®, Korch®, Manesty®, orBonals®). As used herein, the term “non-particulate detergent product”includes physical shapes such as tablets, blocks, bars and the like.

Coating for Non-particulate Detergent Product

In one embodiment, the tablets are coated with a coating in order toprovide mechanical strength and shock and chip resistance to thecompressed tablet core. The tablets are coated with a coating that issubstantially insoluble in water so that the tablet does not absorbmoisture, or absorbs moisture at only a very slow rate. The coating isstrong so that moderate mechanical shocks to which the tablets aresubjected during handling, packing and shipping result in no more thanvery low levels of breakage or attrition. Further, the coating ispreferably brittle so that the tablet breaks up when subjected tostronger mechanical shock. Furthermore it is advantageous if the coatingmaterial is dissolved under alkaline conditions, or is readilyemulsified by surfactants. This avoids the deposition of undissolvedparticles or lumps of coating material on the laundry load. This may beimportant when the coating material is completely insoluble (for exampleless than 1 g/l) in water.

As defined herein “substantially insoluble” means having a very lowsolubility in water. This should be understood to mean having asolubility in water at 25° C. of less than 20 g/L, preferably less than5 g/l, and more preferably less than 1 g/l. Water solubility is measuredfollowing the test protocol of ASTM E 1148-87 entitled, “Standard TestMethod for Measurements of Aqueous Solubility”.

Suitable coating materials are fatty acids, adipic acid and C8-C13dicarboxylic acids, fatty alcohols, diols, esters and ethers. Preferredfatty acids are those having a carbon chain length of from C12 to C22and most preferably from C18 to C22. Preferred dicarboxylic acids areadipic acid (C6), suberic acid (C8), azelaic acid (C9), sebacic acid (C10), undecanedioic acid (C11), dodecanedioic acid (C 12) andtridecanedioic acid (C13). Preferred fatty alcohols are those having acarbon chain length of from C12 to C22 and most preferably from C14 toC18. Preferred diols are 1,2-octadecanediol and 1,2-hexadecanediol.Preferred esters are tristearin, tripalmitin, methylbehenate,ethylstearate. Preferred ethers are diethyleneglycol monohexadecylether, diethyleneglycol mono octadecylether, diethyleneglycolmono tetradecylether, phenylether, ethyl naphtyl ether, 2methoxynaphtalene, beta naphtyl methyl ether and glycerolmonooctadecylether. Other preferred coating materials include dimethyl2,2 propanol, 2 hexadecanol, 2 octadecanone, 2 hexadecanone, 2, 15hexadecanedione and 2 hydroxybenzyl alcohol. The coating is ahydrophobic material having a melting point preferably of from 40° C. to180° C.

In the preferred embodiment, the coating can be applied in a number ofways. Two preferred coating methods are a) coating with a moltenmaterial and b) coating with a solution of the material. In a), thecoating material is applied at a temperature above its melting point,and solidifies on the tablet. In b), the coating is applied as asolution, the solvent being dried to leave a coherent coating. Thesubstantially insoluble material can be applied to the tablet by, forexample, spraying or dipping. Normally when the molten material issprayed on to the tablet, it will rapidly solidify to form a coherentcoating. When tablets are dipped into the molten material and thenremoved, the rapid cooling again causes rapid solidification of thecoating material. Clearly substantially insoluble materials having amelting point below 40° C. are not sufficiently solid at ambienttemperatures and it has been found that materials having a melting pointabove about 180° C. are not practicable to use. Preferably, thematerials melt in the range from 60° C. to 160° C., more preferably from70° C. to 120° C.

By “melting point” is meant the temperature at which the material whenheated slowly in, for example, a capillary tube becomes a clear liquid.For most purposes, the coating forms from 1% to 10%, preferably from1.5% to 5%, of the tablet weight.

Addition of Flow Aids

In the preferred embodiment, the process further includes the step ofadding a flow aid to the particulate detergent composition in a range offrom about 0.1% to about 25% by weight of the particulate detergentcomposition.

As used herein, the term “flow aids” means any material capable of beingdeposited on to the surface of detergent particles so as to reduce thestickiness of the detergent particles and allow them to flow freely.Flow aids could include porous carrier particles selected from the groupconsisting of amorphous silicates, crystalline nonlayer silicates, layersilicates, calcium carbonates, calcium/sodium carbonate double salts,sodium carbonates, clays, zeolites, sodalites, alkali metal phosphates,macroporous zeolites, chitin microbeads, carboxyalkylcelluloses,carboxyalkylstarches, cyclodextrins, porous starches and mixturesthereof.

The preferred flow aids are zeolite A, zeolite X, zeolite Y, zeolite P,zeolite MAP and mixtures thereof. The term “zeolite” used herein refersto a crystalline aluminosilicate material. The structural formula of azeolite is based on the crystal unit cell, the smallest unit ofstructure represented by

Mm/n[(AlO2)m(SiO2)y].xH2O

where n is the valence of the cation M, x is the number of watermolecules per unit cell, m and y are the total number of tetrahedra perunit cell, and y/m is 1 to 100. Most preferably, y/m is 1 to 5. Thecation M can be Group IA and Group IIA elements, such as sodium,potassium, magnesium, and calcium.

In the preferred embodiment of the present invention, the flow aid isadded in an amount in a range, desirably, from about 0.1% to about 25%by weight of the particulate detergent, more desirably from about 1% toabout 15% by weight, preferably from about 1% to about 10% by weight,and most preferably in an amount of about 5% by weight. It isundesirable to add more than 25% by weight of the flow aid because tooexcessive a force would be needed to make the detergent particles tostick together and stay in a particulate form. Flow aid addition in anamount less than about 0.1% by weight is also undesirable because littleor no reduction in the stickiness of the detergent particles wouldoccur, which upon compression into a particulate form would cause theresultant detergent tablet to not disintegrate readily when placed inwater in a washing machine.

In one embodiment, the flow aids have a perfume adsorbed on theirsurface before being deposited on the detergent particles. Preferably,the flow aids are zeolites preferably containing less than about 20%desorbable water, more preferably less than about 8% desorbable water,and most preferably less than about 5% desorbable water. Such materialsmay be obtained by first activating/dehydrating by heating to about 150to 350 C., optionally with reduced pressure (from about 0.001 to about20 Torr). After activation, the perfume is slowly and thoroughly mixedwith the activated zeolite and, optionally, heated to about 60° C. forup to about 2 hours to accelerate absorption equilibrium within thezeolite particles. The perfume/zeolite mixture is then cooled to roomtemperature and is in the form of a free-flowing powder. The term“perfume” is used to indicate any odoriferous material which issubsequently released into the aqueous bath and/or onto fabricscontacted therewith. The perfume will most often be liquid at ambienttemperatures. A wide variety of chemicals are known for perfume uses,including materials such as aldehydes, ketones and esters. Morecommonly, naturally occurring plant and animal oils and exudatescomprising complex mixtures of various chemical components are known foruse as perfumes. The perfumes herein can be relatively simple in theircompositions or can comprise highly sophisticated complex mixtures ofnatural and synthetic chemical components, all chosen to provide anydesired odor. Typical perfumes can comprise, for example, woody/earthybases containing exotic materials such as sandalwood, civet andpatchouli oil. The perfumes can be of a light floral fragrance, e.g.,rose extract, violet extract, and lilac. The perfumes can also beformulated to provide desirable fruity odors, e.g., lime, lemon, andorange. Any chemically compatible material which exudes a pleasant orotherwise desirable odor can be used in the perfumed compositionsherein. Perfumes also include pro-fragrances such as acetalpro-fragrances, ketal pro-fragrances, ester pro-fragrances (e.g.,digeranyl succinate), hydrolyzable inorganic-organic pro-fragrances, andmixtures thereof. These pro-fragrances may release the perfume materialas a result of simple hydrolysis, or may be pH-change-riggeredpro-fragrances (e.g., pH drop) or may be enzymatically releasablepro-fragrances.

In the preferred embodiment, the amount of perfume adsorbed on thecarrier material, such as zeolite for example, is preferably in therange of about 0. 1% to about 50% by weight, more preferably in therange of about 0.5% to about 25% by weight, and most preferably in therange of about 1% to about 15% by weight of zeolite powder.

Compaction of Particulate Detergent to Form Non-particulate DetergentProduct

In the preferred embodiment, the process still further includes the stepof compacting the particulate detergent composition having the flow aidby applying a pressure in an amount sufficient to form thewater-dispersible non-particulate detergent product having a density ofat least about 1000 g/l. It is desirable to form a detergent tablet thathas a density of at least about 1000 g/l so that the tablet will sink inwater. If the density of the detergent tablet is less than about 1000g/l, the tablet will float when placed in the water in a washing machineand this will detrimentally reduce the dissolution rate of the tablet inthe water. It is desirable to apply at least that much pressure as issufficient to compress the particulate detergent material to form atablet having a density of at least about 1000 g/l. Too little apressure will result in a compressed tablet with a density less thanabout 1000 g/l.

EXAMPLE A

Detergent tablets are formed which have a flow aid deposited on thedetergent particles before such particles are compressed into a tabletform, according to the following composition:

TABLE A.1 Ingredients % by weight Detergent particles  95.00 Flow Aid(zeolite A)  5.00 Total 100.00

The detergent particles have the following composition:

TABLE A.2 Particulate detergent Ingredients % by weight C₁₂₋₁₆ linearalkylbenzene sulfonate  8.80 C₁₄₋₁₅ alkyl sulfate/C₁₄₋₁₅ alkyl ethoxysulfate  8.31 C₁₂₋₁₃ alkyl ethoxylate  1.76 polyacrylate (MW = 4500) 2.40 polyethylene glycol (MW = 4000)  0.96 sodium sulfate  8.40aluminosilicate  21.28 sodium carbonate  16.80 protease enzyme  0.32sodium perborate monohydrate  2.08 lipase enzyme  0.17 cellulase enzyme 0.08 NOBS extrudate  4.80 citric acid monohydrate  2.25 sodiumbicarbonate  2.75 sodium acetate  15.00 free water  1.60 other minoringredients (perfume etc.)  2.24 Total 100.00

The detergent tablet formed is coated with a coating according to thefollowing composition:

TABLE A.3 Ingredient % by weight Detergent tablet having flow aid  91.10Coating: dodecanedioc acid  8.00 carboxymethyl cellulose  0.90 Total100.00

The flow aid (zeolite) is added to the particulate detergent compositionand mixed by one of various methods, such as agitation for example, inorder to homogeneously mix the flow aid with the detergent composition..Alternatively, the flow aid is sprayed on the surface of detergentparticle.

The tablets are formed by compressing the tablet ingredients in acylindrical die having a diameter of 55 mm using a laboratory presshaving a trade name Carver Model 3912, to form a tablet having a heightof 20 mm. The formed tablets were then coated with the protectivecoating by dipping the tablet into a molten bath of the coating forabout 3 seconds. The molten coating bath is maintained at a temperatureof about 145 degrees centigrade.

The term “NOBS extrudate” as used herein, is an acronym for the chemicalsodium nonanoyloxybenzene sulfonate, commercially available from EastmanChemicals, Inc. The carboxymethyl cellulose used in the above example iscommercially available from Metsa-Serla and sold under the trade name,Nymcel ZSB-16.

Test for Determining Dispersibility in Water

The following method is used to measure the rate of dispersion (ROD) ofa detergent tablet expressed as percentage residue remaining after “t”minutes, where “t” is 3, 5 and 10 minutes. The equipment used includes a5000 ml glass beaker, a stopwatch with alarm, an electrical stirrer withvariable speed IKA RW 20 DZM or equivalent, a cage made of perforatedmetal gauze (diameter 52 mm, height 40 mm having 16 apertures each ofabout 2.5 mm square) and a weigh scale with accuracy of 0.1 grams.

The method includes the following steps: The beaker is filled with 4000ml (+/−50 ml) of distilled water at 20° C. (+/−1° C.). The cage testeris mounted in the electrical stirrer. A tablet with a known weight isplaced in the cage and the cage is connected to the stirrer. The cage issubmerged in the water with the cage suspended about half way down thebeaker and the stirrer is started at a fixed speed of 80 rpm. Thestopwatch is started. The stirrer is stopped after 3 minutes. The cageis lifted out of the water and the tablet residue remaining in the cageis weighed. The % residue is calculated with the following equation:$\text{\%~~residue} = {\frac{\text{Tablet weight after “}\text{t}\text{” minutes}}{\text{Initial tablet weight}} \times 100}$

The remaining tablet is placed back in the cage and the process isrepeated for an additional 2 and 5 minutes to give yield data for tabletdispersion after 3, 5 and 10 minutes.

As used herein, the term “dispersibility in water” is defined as ameasure of the % residue, as calculated above, after 3 minutes. In otherwords, for example, a detergent tablet which has 5% by weight lessresidue than another detergent tablet would be deemed to have 5% greaterdispersibility in water.

It has been unexpected and surprisingly discovered that thenon-particulate detergent product, e.g., a detergent tablet, has atleast about 5% greater dispersability in water as compared to anothernon-particulate detergent product having a density of at least about1000 g/l but not formulated with a flow aid according to this invention.It has also been unexpectedly found that the water-dispersiblenon-particulate detergent product has at least about 10% greaterdispersability in water as compared to a non-particulate detergentproduct having a density of at least about 1000 g/l and having a flowaid in an amount less than about 1% by weight of the particulatedetergent composition.

It has also been discovered that the water-dispersible non-particulatedetergent product formed by the process of the present invention has atleast about 25% greater dispersability in water as compared to anon-particulate detergent product having a density of at least about1000 g/l and having a flow aid in an amount less than about 2% by weightof the particulate detergent composition.

In the preferred embodiment of the present invention, the flow aid isadded in an amount of about 5% by weight of the particulate detergentcomposition. It has been unexpectedly discovered that by doing so, thewater-dispersible non-particulate detergent product of the presentinvention has at least about 50% greater dispersability in water ascompared to another non-particulate detergent product having a densityof at least about 1000 g/l and having the flow aid in an amount lessthan about 5% by weight of the particulate detergent composition.

In another embodiment of the present invention, a method of launderingfabric materials in a washing machine includes the steps of providing aflexible porous bag adapted for receiving a non-particulate detergentproduct, providing a non-particulate detergent product, placing thenon-particulate detergent product within the flexible porous bag, andplacing the flexible porous bag containing the detergent product in thewashing machine with the fabric materials to be washed.

The flexible porous bag is permeable to water and to the washing mediumand is thus adapted for permitting entry of an aqueous washing mediumthrough the bag, thereby dissolving the non-particulate detergentproduct placed therein, into the aqueous washing medium, and releasing aresultant wash solution from inside of the bag to outside of the bag andinto the aqueous wash medium during a wash cycle.

The flexible porous bag is made of a material capable of retaining thenon-particulate detergent product without allowing it to pass throughuntil the detergent product has dissolved in the washing medium. The bagis also made of a material capable of withstanding the temperatures ofwashing laundry in a washing machine. The process of the invention maybe applied not only to non-particulate detergents but also to anynon-particulate product which is active during washing, such as, forexample, bleaching agents, such as agents releasing chlorine or activeoxygen (peroxygen compounds), bleaching catalysts, bleaching activators,bactericides, foam regulators, whiteners, agents preventing there-deposition of soil, enzymes, softeners, agents capable of removinggrease stains or other constituents having no direct effect on thesoiling but capable of taking part in the laundry washing process.

The flexible bag may be made from any material which offers a sufficientresistance to water, such as a woven or non-woven material produced fromnatural or synthetic fibers. For example, the bag is formed of purecotton either in the form of a fabric with a mesh opening of less thanabout 0.5 mm or in the form of a non-woven article with openings havinga size in a range of from about 0.5 mm to about 0.8 mm.

Accordingly, having thus described the invention in detail, it will beobvious to those skilled in the art that various changes may be madewithout departing from the scope of the invention and the invention isnot to be considered limited to what is described in the specification.

What is claimed is:
 1. A process for producing a water-dispersiblenon-particulate detergent product, comprising the steps of: (a)providing a particulate detergent composition, wherein said particulatedetergent composition is a mixture of a spray dried detergent and anagglomeration detergent comprising a perborate component present in aweight ratio in a range of from about 40:60 to about 80:20, spray dried:agglomeration detergent, the final bulk density of said detergentcomposition being no greater than about 900 g/l; (b) adding a flow aidto said particulate detergent composition in a range of from about 0.1%to about 25% by weight of said particulate detergent composition; and(c) compacting said particulate detergent composition having said flowaid by applying a pressure in an amount sufficient to form saidwater-dispersible non-particulate detergent product having a density ofat least about 1000 g/l.
 2. The process of claim 1 wherein said flow aidis added in an amount of about 5% by weight of said particulatedetergent composition.
 3. The process of claim 1 wherein saidwater-dispersible non-particulate detergent product has at least about5% greater dispersability in water as compared to a non-particulatedetergent product having a density of at least about 1000 g/l but nothaving said flow aid.
 4. The process of claim 1 wherein saidwater-dispersible non-particulate detergent product has in a range offrom about 5% to about 50% greater dispersability in water as comparedto a non-particulate detergent product having a density of at leastabout 1000 g/l but not having said flow aid.
 5. The process of claim 1wherein said water-dispersible non-particulate detergent product has atleast about 10% greater dispersability in water as compared to anon-particulate detergent product having a density of at least about1000 g/l and having said flow aid in an amount less than about 1% byweight of said particulate detergent composition.
 6. The process ofclaim 1 wherein said water-dispersible non-particulate detergent producthas at least about 25% greater dispersability in water as compared to anon-particulate detergent product having a density of at least about1000 g/l and having said flow aid in an amount less than about 2% byweight of said particulate detergent composition.
 7. The process ofclaim 1 wherein said water-dispersible non-particulate detergent producthas at least about 50% greater dispersability in water as compared to anon-particulate detergent product having a density of at least about1000 g/l and having said flow aid in an amount less than about 5% byweight of said particulate detergent composition.
 8. The process ofclaim 1 wherein said flow aid is in the form of porous carrierparticles.
 9. The process of claim 8 wherein said porous carrierparticles are selected from the group consisting of amorphous silicates,crystalline nonlayered silicates, layered silicates, calcium carbonates,calcium/sodium carbonate double salts, sodium carbonates, clays,zeolites, sodalites, alkali metal phosphates, macroporous zeolites,chitin microbeads, carboxyalkylcelluloses, carboxyalkylstarches,cyclodextrins, porous starches and mixtures thereof.
 10. The process ofclaim 8 wherein said porous carrier particles are selected from thegroup consisting of Zeolite A, Zeolite X, Zeolite Y, Zeolite P, ZeoliteMAP and mixtures thereof.
 11. The process of claim 1 wherein the step ofproviding a particulate detergent composition includes providing saiddetergent composition having a bulk density in the range of from about600 g/l to about 850 g/l.
 12. The process of claim 11 wherein the stepof providing a particulate detergent composition includes providing saiddetergent composition having a bulk density in the range of from about625 g/l to about 725 g/l.
 13. The process of claim 1 wherein saidwater-dispersible non-particulate detergent product has at least about10% greater dispersability in water as compared to a non-particulatedetergent product having a density of at least about 1000 g/l and formedfrom a particulate detergent composition having a bulk density nogreater than 700 g/l, when said flow aid is added in an amount greaterthan about 1% by weight of said particulate detergent composition andwhen said particulate detergent composition has a bulk density nogreater than 700 g/l.
 14. The process of claim 1 wherein said flow aidis in the form of a powder homogeneously mixed in said particulatedetergent composition.
 15. The process of claim 1 wherein said flow aidsubstantially covers the surface of said particulate detergentcomposition.